Recharging and/or remanufacturing used laser, fax, copier, etc. cartridges presents many anomalies never encountered by original equipment manufacturers since they build their equipment to run through only one cycle. Recycling is not an objective for their Engineers, i.e., it is not in their best financial interests.
Furthermore, due to the trend to build laser printers, plain paper fax machines and copiers more compact, predictable impediments to recycling (remanufacturing) certain cartridges have occurred. Such is the case with resealing a rectangular toner hopper transfer opening on a laser printer cartridge and it's sister plain paper fax cartridge. The hopper opening on these cartridges is recessed making it very difficult to install a new seal into it. A second impediment on these cartridges is an obstructed lower lip of the opening flange by a welded in spacer that covers about 76.5% of the lip, leaving only 23.5% available to mount the bottom of the seal to. The O.E.M. seal has apparently been installed before the spacer was ultrasonically welded in place since it is attached to the full bottom lip of the flange, i.e. also the part obstructed by the spacer. The third impediment is a restricted seal pullstrip exit port or slot that is only 0.25" wide.
Aftermarket seals may fall into three classifications, peel off seals, tear out seals, and hard card seals that slid into slots around the perimeter of the hopper opening effectively sealing the off the toner hopper.
Of these seals, the peel off and the tear out have been used for the above described cartridges with their impediments.
To overcome the first impediment, the recessed flange, seal makers use either a thick flat stiff seal baseplate or a thin flat seal and make it stiff by attaching a piece of cardboard to the front that is removed after it is in place. The thick seal baseplates are made to almost the exact width size and as a result there is less chance for the seal to be maligned. Thick seals of 0.020" or more have demonstrated that toner lumps build up on the thick edge and block the toner transfer through the slot in the seal baseplate. Thin seals of course do not have this problem, but, are much more prone to become maligned, crimped, and become bowed in the center if pressed too hard against the flange. A bowed seal may have a narrowed slot when the seal is pulled out.
The second impediment, not enough of the lower lip of the toner opening flange available to attach a seal to. Only approximately 1/4 of the area available that the Original Equipment Manufacturer used to attach their seal to. Also, the original equipment manufacturer had a new clean plastic flange to attach a seal to unlike the remanufacturer that has to work with a used cartridge that is contaminated with toner residue and the remains of the O.E.M. seal and it's adhesive. The best designed current aftermarket seals that seal effectively, have a thick baseplate and a narrow slot. This design prevents the bottom of the seal from bowing up and over the limited exposed lower flange lip. These seals are made with only perhaps 0.005" to 0.010" tolerance for the overall width. Being very rigid it is much more difficult for these seal baseplates to ride up over the narrow bottom exposed flange lip. Also their rigidity tends to hold every segment of the bottom against the narrowed lower flange lip.
These seals are of the peel off type and were used successfully for perhaps a few years. Then something changed that resulted in insufficient toner transfer through the narrow baseplate slot. Unacceptable customer returns of remanufactured cartridges were experienced.
Thin seals are almost impossible to insert into the flange area and as a result one manufacturer of aftermarket seals in Belgium has marketed a thin fabric seal that tears out like the O.E.M. seal. This thin seal has a piece of cardboard stiffener attached to the front by a lower tact adhesive to aid in installation. This seal is still difficult to position. Even when they are in position the pressure required to effectively engage the high tact adhesive to the flange may dislodge the seal from the bottom or bow the seal. Since there is no rigidity to the seal itself, poor adhesion along the bottom lip will result in toner leakage. To further aggravate the situation, when the cardboard stiffener insertion aid is pulled off the seal, the force required to remove it may be enough to pull off or loosen the seal from the flange. This is highly possible even though the cardboard held to the seal with a low tact adhesive. The reason that can happen is the area of adhesion of the cardboard to the front of the seal is much greater than the area of adhesion on the back of the seal to the hopper flange. The area of adhesion of the low tact adhesive to the cardboard is about 2.3 times greater than the area of the high tact adhesive on the back of the seal to the flange. To even further exacerbate the problem, when the end of the cardboard is peeled off the front of the seal, it must be pulled up and out to avoid the front part of the trough for the magnetic roller section. Therefore, most of the resistance to the peel off force must come from the insufficient area of the lower flange lip. Attempting to reseal the loosened seal after removal of the installation tool could easily result in pushing it up over the bottom lip or crimping it. Thin seals are the worst choice for the inadequate and contaminated lower lip adhesive area.
The third impediment is the limited seal exit port or slot that restricts the seal width to only 0.25". Since the toner hopper transfer opening is 0.578" (wide including the flange) the seal assembly must be that wide. Obviously, the 0.25" seal that pulls out is not large enough to cover the total opening. This is accomplished with a cover or baseplate that stays in the cartridge after the seal has been pulled. The baseplate can be plastic or other material and has a slot in its central section for toner passage that the 0.25" seal covers up and/or seals. Since the seal is only 0.25" wide, the slot cannot be that wide. The seal must have enough overlap all the way around the perimeter of the slot to seal it. By common sealing techniques of glue, heat sealing or pressure sensitive adhesives, the overlap should be at least 1/16" (0.0625") all the way around. Subtracting this overlap from the width of 0.25", that is 0.25"-2(0.0625")=0.125" for the slot width. Therefore, necessary overlap reduces the effective toner transfer slot down about 0.125". This type of seal has worked well in the past as stated above, but, does not function well anymore. The slot is not wide enough to always transfer enough toner through it to the magnetic metering roller section. This may be due in part to formulation changes in the toner available to rechargers. The current toners tend to cake and/or form small lumps in more humid conditions which is possibly due to some hydrophilic component added to the toner. When the cover or seal baseplate is thick, about 0.020", toner piles up on it and blocks the narrow slot. Toner transport through the narrow slot very unpredictable. In addition, the rubber of the beater bars used to push the toner through the hopper transfer slot become fatigued after several recharging cycles. As a result the toner has a diminished force exerted on it that is not adequate to force it through a narrow slot. This is well stated in the March 1995 "Recharger Magazine", 4218 W. Charleston Blvd., Las Vegas, N.V. 89102. The article is titled "The LX Toner Starvation Phenomenon" by Dr. John Wyhof of Static Control Components, Inc., phone (919) 774 3808.
The other way to deal with toner starvation problems is to use tear out seals. The two basic types used are the O.E.M. fabric on new cartridges only and the perforated plastic film, paper, and metal foils. The O.E.M. patent is U.S. Pat. No. 4,931,838 "Developing Apparatus And Process Cartridge Having The Same". There is one O.E.M. type fabric tear out seal with a new adjuvant for installation into remanufactured cartridges. It is manufactured by CF Distributors of Belgium. The seal is mentioned above and utilizes a cardboard stiffener to aid in installation. The CF seal is advertised as having a patent applied for and that application may be under the name of Jon DeKesel. The original equipment manufacturers seal is not suitable for remanufactured cartridges due to the inaccessibility of the full lower lip of the flange and the recessed flange.
The only applicable patent for remanufacturing is U.S. Pat. No. 5,110,646, "Process And Materials For Reconditioning A Toner Cartridge". This patent utilizes a perforated tear out polypropylene film. This seal could work as far as the width of the slot is, but, polypropylene is a tough synthetic plastic film and would be hard to tear out unless it were perforated rigorously. The necessary perforations claimed by the patent do have many large holes in them for toner to leak out. Claim 4 of the patent calls for perforations from 50 to 72 cuts per inch. With standard perforations that means there are 0.013" cuts followed by 0.007" spaces (uncut paper) for the 50 cuts per inch and for the 72 cuts per inch there are 0.007" cuts followed by 0.007" spaces. Clearly, half the film is cut away with the 72 cuts per inch and more than half the film is cut away for the 50 cuts per inch. This might not be bad for some applications, but, toner particles are very fine and dense. Their size ranges from 7 (0.000275") microns to 12 microns (0.000472"). The density of single component toner is relatively high since it contains about 44% w/w magnetite or magnetic iron. Equating the smaller particle size of toner to the cuts of the 72 cuts per inch means the cuts are 25 times as large as the 7 micron size and the cuts of the 50 cuts per inch are 42 times as large as the smaller 7 micron size toner particles. This will of course allow for significant leakage not only the smaller toner particles, but, also leakage of the larger 12 micron size particles and larger. To further exacerbate the leakage problem, synthetic films are stressed during processing to improved physical properties. Once the stress is relieved by cutting, the edges of the cut will curl and no longer remain in the plane of the film. The cuts might appear as tiny funnels under magnification.
The other thin seal by CF Supplies of Belgium is a thin flat seal that is difficult to install and has all the problems as mentioned above under the second impediment. They are propensity to bow and lose adhesion to the contaminated limited lower lip of the flange, i.e. it is absurd to think that a thin aftermarket seal could securely be attached to only 23.5% of the lip without the other 67.5% that the O.E.M. engineered as necessary for their thin cloth seal.
It thus is an object of this invention to provide the folling devices and advantages:
a. to provide a seal assembly for resealing used laser printer, plain paper fax, and electrostatic copy cartridges for remanufacturing that will not leak toner. PA1 b. to provide a thin, but, rigid seal assembly that can be installed easily onto a toner hopper opening flange that is in a recessed area. PA1 c. to provide a seal assembly that utilizes an L shaped seal baseplate whereby the adhesive under said leg is used to securely attach the bottom of the seal assembly to the toner hopper. The said leg is securely attached to the spacer that is perpendicular to the lower lip of the flange that obstructs about 76.5% of it. The said leg more than compensates for the obstructed part of the flange in terms of bonding area and it is also more resistant to the force exerted on it by toner in the hopper. That is the resistance of the said leg's bond to the spacer is directly opposite the force exerted by toner in the hopper in transit. The bonds to the flange are perpendicular to the force exerted by the toner and therefore less resistant. In addition the bond of the said leg to the spacer prevents the bottom of the seal from being pushed up over the 23.5% of the exposed lower lip as happens with flat seals. PA1 d. to provide a means whereby the bottom of the assemble's said leg can be slid so the assembly back can be positioned against the flange utilizing an adhesive release paper or other release material under the said leg's adhesive, then said release can be removed after seal assembly back is secured against the flange. PA1 e. To provide toner transfer slot opening in the seal baseplate assembly that is consistently equal to or greater than the seal exit port slit opening. PA1 f. To provide said toner baseplate slot opening 0.1875" wide up to 0.250" wide or greater to prevent toner starvation and/or white out sections or streaks in prints where there is no toner available to print the image. PA1 g. to provide a 0.145" wide by 0.002" to 0.005" thick strong precision made pullstrip that is bonded to the back side of a natural precursor friable film seal. The said pullstrip forcible tears out the section of the film bonded to it in the film's direction of orientation and that is parallel to the toner hopper transfer slot opening. The said strong precision pullstrip assures that the resultant slot in the film seal will be consistently at least as wide as the said pullstrip. PA1 h. To provide a natural precursor film seal from cellulose that tears preferentially along the direction of molecular orientation and therefore does not require any perforations to assure its tear out in a preferred direction. Without perforations the film is impervious to toner particles. PA1 i. To provide an oriented natural precursor film seal material from cellulose that will not generate enough static that could be deleterious to the functioning of the printing as synthetic films could. PA1 j. to provide said natural precursor film seal that will not generate static significant static and thereby holding toner by static attraction that blocks the transfer slot opening. PA1 k. to provide a seal that effectively attaches to the toner hopper flange utilizing a 72 oz high tact pressure sensitive adhesive with a carrier. Said adhesive is a double sided tape with a thin plastic film in the center called a carrier. The adhesive has a tolerance for plastizers and other materials that may contaminate the adhesive bonding surface of the toner hopper and its flange, i.e. the adhesive will not loosen its bond to the surface due to the migration of contaminants into it. PA1 l. to provide the same and/or equal tact adhesive on the front of the seal to securely hold the precision pullstrip to the front of the baseplate. PA1 m. To provide an adhesive nulled or voided zone on the left edge of the front of the baseplate under the start of the peelback of the pullstrip starting at the left edge extending into at least 0.010" to 0.020" and it's height may be only a projection of the baseplate slot width or may run up to the total baseplate width. Said adhesive nulled zone is to prevent the adhesive's liner from pulling away from the front of the baseplate. The said adhesive nulled or voided zone is on the front side of the adhesive's carrier adjacent to the pullstrip and would be bonded to the pullstrip without said nulled or voided zone. That is the pullstrip is not secured with adhesive up to the edge of the baseplate on the start of the peelback side. Without this zone the propensity for the carrier to stay attached to the pullstrip may be equal to that for it to remain on the baseplate. In other words half of the time the pullstrip would delaminate the carrier from the baseplate and jam up in the exit port slit which would be a seal removal failure. Also it is possible to lift the whole baseplate from the toner hopper flange since that bond may not be quite as strong as the bond to the pullstrip due to contamination on the flange. PA1 n. to provide a 0.005" thick layer or thicker layer of adhesive on the front of double sided adhesive's carrier on the front of the baseplate such that said adhesive layer is thicker than or equal to the pullstrip's thickness thereby embedding the pullstrip into said adhesive layer level with the pullstrips outer surface. With the outer surface of the pullstrip bonded to the cellulose film seal and the cellulose film overlapping the pullstrip bonded to the adhesive, the pullstrip is therefore totally encased so that toner cannot leak around it. That is the cellulose seal is bonded continuously over the baseplate opening and the pullstrip lengthwise over the baseplate's slot. PA1 o. to provide a 0.005" thick or thicker layer of high tact adhesive with a carrier for uniform coverage on the front of the seal that holds the friable oriented cellulose seal firmly in place when the pullstrip tears out a section of it in the direction of the film's molecular orientation to form a toner transfer slot. Said thick layer of high tact adhesive holds the friable cellulose film securely in place and prevents it from delaminating from the baseplate instead of tearing out a swatch equal or greater in width than the pullstrip bonded under it. PA1 p. to provide an adhesive release with a lip under the baseplate's leg and folded up parallel to the seal as a means of holding the seal assembly upright on the leg in the magnetic roller section when the hopper section is in upright position as per operating orientation in the machine. The seal assembly can then be held down to the floor in the section and then slid back against the toner hopper flange. This can be accomplished by hand or with a plastic spatula or other similar devices on the fold of the leg to the upright seal section of the seal assembly. PA1 q. to provide a rigid seal assembly with a thickness of only of 0.005" to 0.015" plastic baseplate by utilizing a fold to enhance rigidity. PA1 r. To provide a pullstrip uniform in thickness of 0.002" to 0.005" with a width of from approximately 0.145" to a limit of 0.250" and said pullstrip that guides a friable seal tear out accurately across the whole length of the baseplate slot. PA1 t. to provide a polyethylene terephthalate pullstrip that is strong enough to pull out a strip of Cellophane by tearing it along the direction of orientation of the molecules much the same way wood is split along its grains. PA1 u. to provide a lower tact adhesive from approximately 32 once to 50 once tact on the front of the adhesive's carrier on the front of the baseplate. The said adhesive would always release the pullstrip and never delaminate the adhesive's carrier from the baseplate or pull the baseplate from the toner hopper flange. The said lower tact adhesive layer would be the layer of adhesive on the front side of the adhesive's carrier directly bonded to the pullstrip. There would be no need for an adhesive nulled zone at the start of the pullstrip's peelback. The bond between the pullstrip and the adhesive's carrier would be significantly less than the bond between the adhesive's carrier and the baseplate. The carrier would always stay bonded to the baseplate and never delaminate. The said lower tact adhesive would also be significantly less tact than the high 72 once tact adhesive on the back side of the baseplate, i.e. the adhesive on each side of the adhesive's carrier on the back side of the baseplate. Some moderate contamination of the flange bonding surface would therefore not weaken the bond of the baseplate enough for the pullstrip to pull the baseplate off the flange instead of tearing out the seal. PA1 v. to provide a seal assembly with the slot torn out by the pullstrip can have it's bottom edge juxtapose to top edge of bottom lip of the toner hopper opening flange. The said slot would be effectively as low as possible and therefore facilitate the transfer of toner into the magnetic roller metering section. This could be important for hoppers that have been recycled many times and their rubber beater bars are fatigued and cannot place sufficient force on the toner to push it through a higher slot opening. The said slot can be that low since the bottom section of the baseplate is held in place by the leg of the seal to the spacer that is perpendicular to the plane of the flange. That is the center can be cut out of the baseplate and extend down to the horizontal leg with no vertical section necessary to butt against the exposed lower lip. There is no need to use the top of the lower lip to bond the seal to since the bottom of the seal is more firmly attached by the leg to the top of the spacer that is perpendicular to the flange's lower lip than if it were bonded only to the 23.5% of the lower lip of the flange. The seal film can be attached to the top of the leg and effectively seal the larger slot in the baseplate. The baseplate ends are the only parts that need to be formed or bent to a 90 degree angle to make the right angle leg off the body of the baseplate. The rigidity will be less without the fold all along the bottom of the baseplate. Extra rigidity can be can be obtained if necessary by using a thicker baseplate since the will be no vertical component on the bottom of the baseplate for toner to build up on. PA1 w. to provide a seal assembly that does not require that the old lower half of the O.E.M. seal be left in place on the toner hopper flange. Though old seal is not needed to prevent the new seal from riding up over the narrow exposed lower lip of the toner hopper flange.
s. To provide a seal film from cellulose a natural precursor that is dissolved and regenerated into a film. This natural based material does not generate deleterious amounts of static as does synthetic polymer films. This material is made by dissolving Cellulose in carbon disulfide in the presence of sodium hydroxide to form a viscous solution called viscose, in which the cellulose molecule has been degraded to an average chain length of 400 to 500 C.sub.6 units. After ripening for eight days the viscose is extruded through a slot into a coagulating bath where the viscose is regenerated into a cellulose film called cellophane. The said film has a molecular orientation.
Further objects and advantages are a replacement seal assembly for remanufacturing that is easy to install, inexpensive to manufacture and can be reproduced in quantity with good quality. Still further objects and advantages will become apparent from a consideration from the ensuing description and drawings.